Transendothelial migration of colon carcinoma cells requires expression of E-selectin by endothelial cells and activation of stress-activated protein kinase-2 (SAPK2/p38) in the tumor cells.

Adhesion and migration of tumor cells on and through the vascular endothelium are critical steps of the metastatic invasion. We investigated the roles of E-selectin and of stress-activated protein kinase-2 (SAPK2/p38) in modulating endothelial adhesion and transendothelial migration of HT-29 colon carcinoma cells. Tumor necrosis factor alpha (TNF alpha) strongly increased the expression of E-selectin in human umbilical vein endothelial cells (HUVEC). This effect was independent of the activation of SAPK2/p38 induced by TNF alpha. Adhesion of HT-29 cells on a monolayer of HUVEC pretreated with TNF alpha was dependent on E-selectin expression but was independent of SAPK2/p38 activity of both HUVEC and tumor cells. The adhesion of HT-29 cells to E-selectin-expressing HUVEC led to the activation of SAPK2/p38 in the tumor cells as reflected by the increased phosphorylation of the actin-polymerizing factor HSP27 by mitogen-activated protein kinase 2/3, a direct target of SAPK2/p38. Moreover, a recombinant E-selectin/Fc chimera quickly increased the activation of SAPK2/p38 in HT-29 cells. Blocking the increased activity of SAPK2/p38 of HT-29 cells by SB203580 or by expressing a dominant negative form of SAPK2/p38 inhibited their transendothelial migration. Similarly, HeLa cells stably expressing a kinase-inactive mutant of SAPK2/p38 showed a decreased capacity to cross a layer of HUVEC. Overall, our results suggest that the regulation of transendothelial migration of tumor cells involves two essential steps as follows: adhesion to the endothelium through adhesion molecules, such as E-selectin, and increased motogenic potential through adhesion-mediated activation of the SAPK2/p38 pathway.

Mineral composition of some traditional Mexican teas.

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots of Tagetes lucida, T. filifolia, Elytraria imbricata, and Holodiscus dumosus, and from root xylem of Ceanothus depressus and Phaseolus ritensis. Native uses of these teas are also described.

Intake and subsequent fate of a ceramic particle containing 2.85 microCi 241Am: a case study.

Intake of 241Am was reported in a young female technologist. External monitoring, whole body counting, urinalysis and fecal analysis were performed to determine the subsequent fate of the contaminant. Five days later, more than 99.5% of the radioactivity was voided in a fecal sample. A single particle, containing 2.85 microCi of 241AmO2 incorporated in a ceramic matrix, was isolated from the fecal sample. Brief descriptions of the radioanalytical results and dosimetry implications are presented. A shadow shield whole body counter was conveniently used to make an early estimate of the intake. This initial estimate enabled staff to decide that it was not necessary to artifically remove the contaminant. It was estimated that the lower large intestine was the organ which received the highest dose due to the passage of the ceramic particle. Systemic uptake of 241Am was indicated by urinalysis. The fractional transfer of 241Am from the GI tract to the blood was estimated to be less than 6 X 10(-5). This maximum estimate is limited by the MDA of the analytical procedures used. The fractional transfer of the 241Am from the GI tract to blood in this case is about an order of magnitude less than recent ICRP recommendations for "all compounds of americium".